Receiving device and method, and communicating system

ABSTRACT

Communication reception that enables reception of a packet which may not contain an error without invalidating the same is disclosed. In one example, an information analyzing unit analyzes a data string and frame/slot information, and supplies TMCC information, slot header information, and data length information to a packet length indicating unit and a packet dividing unit. The packet length indicating unit defines the packet length in advance, and indicates the defined packet length to the packet dividing unit. The packet dividing unit performs packet division on the basis of the packet length obtained from the TMCC information, the slot header information, the data length information and the like from the information analyzing unit, and the packet length defined by the packet length indicating unit.

TECHNICAL FIELD

The present disclosure relates to a receiving device and a method, and acommunicating system, and especially relates to a receiving device and amethod, a communicating system capable of receiving a packet which maynot include an error without invalidating the same as much as possible.

BACKGROUND ART

In digital television broadcasting, video and audio are divided intopacket units and multiplexed to be transmitted. As a classification of apacket, there is a fixed length packet and a variable length packet. Anexample of the variable length packet is a type length value (TLV)packet of advanced broadband digital broadcasting (advanced BS).Hereinafter, the variable length packet is simply referred to as apacket.

In multiplexed transmission, error correction coding is performed on atransmitting side, and decoding is performed on a signal sent as amultiplexed stream on a receiving side. In general, a unit of errorcorrection coding/decoding (referred to as a block, slot and the like)and a unit of a packet does not coincide with each other, and the packetsteps over a plurality blocks or a plurality of packets are present inone block.

In general, the packet includes a header and a data part. A length(packet length) of the packet may be known from a parameter indicating adata length stored in the header. On the receiving side, there is a casewhere information formatted to the packet unit is output from the datalength and information indicating a boundary of the packet such assystem information.

If a receiver fails in error correction decoding of a certain block in atransmission stream, all packets using even a little bit of a decodingresult of the block are invalidated. In the packet to be invalidated,since the data length stored in the header of the packet might beerroneous, a series of packets are invalidated (refer to Patent Document1).

CITATION LIST Patent Document

-   Patent Document 1: Japanese Patent Application Laid-Open No.    2009-201117

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

As described above, due to the failure in decoding of a certain block,adjacent packets are invalidated irrespective of whether there is anerror in the packet. As a result, “the packet which does not contain anerror” which may be used essentially for decoding/playback or recordingmight be invalidated. Therefore, there is a need for a method that doesnot invalidate as much as possible packets that may not contain errors.

The present disclosure is achieved in view of such a situation, and itis possible to receive a packet which may not contain an error withoutinvalidating the same as much as possible.

Solutions to Problems

A receiving device according to one aspect of the present technology isprovided with an information analyzing unit which analyzes packetinformation regarding a packet from a transmitted multiplexed stream, apacket length indicating unit which defines a packet length, and apacket dividing unit which divides the multiplexed stream into packetsby using at least one of the packet information analyzed by theinformation analyzing unit and the packet length indicating the packetlength defined by the packet length indicating unit.

The packet dividing unit may divide the multiplexed stream into packetsby using the packet length in the packet information analyzed by theinformation analyzing unit or the packet length indicating the packetlength defined by the packet length indicating unit according to acomparison result between the packet length in the packet informationanalyzed by the information analyzing unit and a range of the packetlength defined by the packet length indicating unit.

The packet dividing unit may divide the multiplexed stream into packetsby using the packet length in the packet information in a case where itis determined that the packet length in the packet information analyzedby the information analyzing unit falls within the range of the packetlength defined by the packet length indicating unit.

The packet dividing unit may divide the multiplexed stream into packetsby using the packet length defined by the packet length indicating unitin a case where it is determined that the packet length in the packetinformation analyzed by the information analyzing unit is out of therange of the packet length defined by the packet length indicating unit.

In a case where the packet divided on the basis of the packet lengthdefined by the packet length indicating unit is the packet having anon-standard short packet length, the packet dividing unit may adjust adivided position with an immediately preceding packet length orinvalidate the packet having the short packet length.

The packet dividing unit may rewrite header information of animmediately preceding packet when dividing the packet.

The header information is a synchronous byte, type information, or adata length at the time of division.

The packet dividing unit may add additional information defined by atransmission protocol when dividing the packet.

The packet length indicating unit may define the packet length by usinga result of learning the packet length from the packet length with whichdivision processing is performed previously.

The packet length indicating unit may define a range of the packetlength by using a result of learning the packet length from the packetlength with which the division processing is performed previously.

The packet is a type length value (TLV) packet.

The packet information is at least one of transmission and multiplexingconfiguration control information (TMCC information), slot headerinformation, and data length information.

The packet information is at least one of BB Frame header informationand data length information.

The packet information is at least one of divided TLV packet headerinformation and data length information.

In a receiving method according to one aspect of the present technology,a receiving device analyzes packet information regarding a packet from atransmitted multiplexed stream, defines a packet length, and divides themultiplexed stream into packets by using at least one of analyzed packetinformation and defined packet length.

A communicating system according to another aspect of the presenttechnology is provided with a transmitting device provided with atransmitting unit which divides a signal into packets and transmits amultiplexed stream obtained by multiplexing the divided packets, aninformation analyzing unit which analyzes packet information regardingthe packet from the multiplexed stream transmitted by the transmittingdevice, a packet length indicating unit which defines a packet length,and a packet dividing unit which divides the multiplexed stream intopackets by using at least one of the packet information analyzed by theinformation analyzing unit and the packet length indicating the packetlength defined by the packet length indicating unit.

In one aspect of the present technology, the packet informationregarding the packet is analyzed from the transmitted multiplexed streamand the packet length is defined. Then, the multiplexed stream isdivided into packets using at least one of the analyzed packetinformation and the defined packet length.

In another aspect of the present technology, the signal is divided intopackets by the transmitting device, and the multiplexed stream in whichthe divided packets are multiplexed is transmitted. Also, the packetinformation regarding the packet is analyzed from the transmittedmultiplexed stream by the receiving device, and the packet length isdefined. Then, the multiplexed stream is divided into packets using atleast one of the analyzed packet information and the defined packetlength.

Effects of the Invention

According to the present technology, it is possible to receive a packetwhich may not contain an error without invalidating the same as much aspossible.

Meanwhile, an effect described in this specification is merely anexample; an effect of the present technology is not limited to thatdescribed in this specification and an additional effect may also beobtained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view illustrating a configuration example of a communicatingsystem to which the present technology is applied.

FIG. 2 is a block diagram illustrating a configuration example of areceiving device.

FIG. 3 is a block diagram illustrating a configuration example of avariable length packet processing unit.

FIG. 4 is a view illustrating a method of detecting TLV packet boundaryinformation.

FIG. 5 is a flowchart illustrating reception processing of the receivingdevice.

FIG. 6 is a flowchart illustrating variable length packet divisionprocessing at step S14 in FIG. 5.

FIG. 7 is a view illustrating the variable length packet divisionprocessing in FIG. 6.

FIG. 8 is a flowchart illustrating another example of the variablelength packet division processing at step S14 in FIG. 5.

FIG. 9 is a view illustrating the variable length packet divisionprocessing in FIG. 8.

FIG. 10 is a flowchart illustrating the variable length packet divisionprocessing at step S14 in FIG. 5.

FIG. 11 is a view illustrating the variable length packet divisionprocessing in FIG. 10.

FIG. 12 is a flowchart illustrating the variable length packet divisionprocessing at step S14 in FIG. 5.

FIG. 13 is a view illustrating the variable length packet divisionprocessing in FIG. 12.

FIG. 14 is a flowchart illustrating still another example of thevariable length packet division processing at step S14 in FIG. 5.

FIG. 15 is a view illustrating the variable length packet divisionprocessing in FIG. 14.

FIG. 16 is a flowchart illustrating still another example of thevariable length packet division processing at step S14 in FIG. 5.

FIG. 17 is a view illustrating the variable length packet divisionprocessing in FIG. 16.

FIG. 18 is a view illustrating overwriting division processing.

FIG. 19 is a view illustrating the overwriting division processing.

FIG. 20 is a view illustrating the overwriting division processing.

FIG. 21 is a view illustrating a method of setting a defined value of apacket length.

FIG. 22 is a view illustrating another method of setting the definedvalue of the packet length.

FIG. 23 is a view illustrating a configuration example of a cableretransmitting system to which the present technology is applied.

FIG. 24 is a block diagram illustrating a configuration example of thereceiving device.

FIG. 25 is a block diagram illustrating a configuration example of avariable length packet processing unit.

FIG. 26 is a view illustrating a method of detecting packet boundaryinformation in a BB Frame.

FIG. 27 is a view illustrating a method of detecting the packet boundaryinformation in a divided TLV packet.

FIG. 28 is a flowchart illustrating reception processing of thereceiving device.

FIG. 29 is a flowchart illustrating variable length packet divisionprocessing at step S214 of FIG. 28.

FIG. 30 is a view illustrating the variable length packet divisionprocessing in FIG. 29.

FIG. 31 is a flowchart illustrating the variable length packet divisionprocessing at step S214 in FIG. 28.

FIG. 32 is a view illustrating the variable length packet divisionprocessing in FIG. 31.

FIG. 33 is a flowchart illustrating the variable length packet divisionprocessing at step S214 in FIG. 28.

FIG. 34 is a view illustrating the variable length packet divisionprocessing in FIG. 33.

FIG. 35 is a flowchart illustrating the variable length packet divisionprocessing at step S214 in FIG. 28.

FIG. 36 is a view illustrating the variable length packet divisionprocessing in FIG. 35.

FIG. 37 is a view illustrating comparison between advanced BSbroadcasting and cable retransmission.

FIG. 38 is a block diagram illustrating a configuration example of apersonal computer.

MODE FOR CARRYING OUT THE INVENTION

Modes for carrying out the present disclosure (hereinafter, referred toas embodiments) are hereinafter described. Meanwhile, the description isgiven in the following order.

1. First Embodiment (Advanced Broadband Digital Broadcasting)

2. Second Embodiment (Cable Retransmission)

3. Third Embodiment (Personal Computer)

1. First Embodiment (Advanced Broadband Digital Broadcasting)

<Configuration Example of Communicating System of Present Technology>

FIG. 1 is a view illustrating a configuration example of a communicatingsystem to which the present technology is applied.

In the example in FIG. 1i , a communicating system 1 includes atransmitting device 11 which divides a broadcast signal of advancedbroadband digital broadcasting (hereinafter also referred to as advancedBS) into packet units and multiplexes them to transmit, and a receivingdevice 12 which receives the broadcast signal divided into the packetunits to be multiplexed.

In the communicating system 1, a type length value (TLV) packet being avariable length packet is used. Meanwhile, in this embodiment, thevariable length packet is hereinafter sometimes simply referred to as apacket appropriately.

<Configuration Example of Receiving Device>

FIG. 2 is a block diagram illustrating a configuration example of thereceiving device in FIG. 1.

The receiving device 12 also is a signal processing device whichreceives the broadcast signal received by an antenna 13 and performspredetermined signal processing thereon. Data on which the signalprocessing is performed by the receiving device 12 is output to a dataprocessing device 14 including a decoder and the like at a subsequentstage.

The receiving device 12 includes a tuner unit 21, a demodulationprocessing unit 22, an error correction decoding processing unit 23, anda variable length packet processing unit 24.

The tuner unit 21 performs RF processing on the broadcast signalreceived by the antenna 13 and outputs the signal after the RFprocessing to the demodulation processing unit 22. The demodulationprocessing unit 22 performs demodulation processing on the signal afterthe RF processing and outputs digital signals 0 and 1 obtained as aresult of demodulation to the error correction decoding processing unit23.

The error correction decoding processing unit 23 performs errorcorrection decoding processing such as LDPC, BCH, Reed Solomon, andconvolutional code, and outputs a data string after the error correctiondecoding processing to the variable length packet processing unit 24. Atthat time, the error correction decoding processing unit 23 alsosupplies error correction information and frame/slot information to thevariable length packet processing unit 24.

The variable length packet processing unit 24 performs variable lengthpacket division processing according to whether the error correction ofa slot M and a slot M-1 of the data string after the error correctionprocessing is successful or failed by using the error correctioninformation and the frame/slot information from the error correctiondecoding processing unit 23. The variable length packet processing unit24 outputs a packet string obtained by packet division to the dataprocessing device 14 at the subsequent stage.

<Configuration Example of Variable Length Packet Processing Unit>

FIG. 3 is a block diagram illustrating a configuration example of thevariable length packet processing unit.

The variable length packet processing unit 24 includes an informationanalyzing unit 41, a packet length indicating unit 42, and a packetdividing unit 43.

The data string and the frame/slot information from the error correctiondecoding processing unit 23 are input to the information analyzing unit41 and the packet dividing unit 43. The error correction informationfrom the error correction decoding processing unit 23 is input to thepacket dividing unit 43.

The information analyzing unit 41 analyzes the data string and theframe/slot information and supplies transmission and multiplexingconfiguration control information (TMCC information), slot headerinformation, and data length information to the packet length indicatingunit 42 and the packet dividing unit 43.

The packet length indicating unit 42 defines a packet length in advanceand indicates the defined packet length to the packet dividing unit 43.Meanwhile, the packet length may be defined to be, for example, a packetsize upper limit provided in terms of standard and operation. Inaddition, as is described later in detail, for example, the packetlength may also be updated on the basis of a result of learning thepacket length with which the division processing is performed.

The packet dividing unit 43 performs the packet division on the basis ofat least one of the information (TMCC information, slot headerinformation, and data length information) from the information analyzingunit 41 and the packet length indicated by the packet length indicatingunit 42. As for the packet length, especially, the packet dividing unit43 performs the packet division on the basis of the packet lengthobtained by the information (TMCC information, slot header information,and data length information) from the information analyzing unit 41 orthe packet length indicated by the packet length indicating unit 42. Thepacket string obtained by division by the packet dividing unit 43 isoutput to the data processing device 14 at the subsequent stage. Thepacket dividing unit 43 outputs packet division information beinginformation of a position of division to the information analyzing unit41. Meanwhile, the packet dividing unit 43 includes a buffer.

<Configuration Example of TLV Packet>

Next, a method of detecting TLV packet boundary information is describedwith reference to FIG. 4.

In the example in FIG. 4, a TLV packet configuration is illustrated. ATLV packet includes a plurality of slots. The slot includes a slotheader including a head pointer and an undefined part, and a pluralityof packets. The packet includes a packet header includingsynchronization, type, and data length, and a data string.

The TLV packet boundary information configured in this manner may bedetected from four types of information indicated by 1 to 4 in FIG. 4.

1 indicates a head pointer by the TMCC.

2 indicates a final pointer by the TMCC.

3 indicates a head pointer by the slot header.

4 indicates packet length cumulative information of the packet header.

Herein, 1 and 2 may be detected from the TMCC, and 3 and 4 may bedetected from the data string.

Meanwhile, robustness of information becomes higher in descending orderof 1 to 4. In addition to the data string included in the packet, forexample, a head/final boundary position pointer in each error correctionblock (slot) is stored in system transmission information (TMCC) that ismore robust than the data string.

<Processing Example of Receiving Device>

Next, a reception processing of the receiving device 12 is describedwith reference to a flowchart in FIG. 5.

At step S11, the tuner unit 21 performs the RF processing on thebroadcast signal received by the antenna 13 and outputs the signal afterthe RF processing to the demodulation processing unit 22. At step S12,the demodulation processing unit 22 performs the demodulation processingon the signal after the RF processing and outputs digital signals 0 and1 obtained as a result of the demodulation to the error correctiondecoding processing unit 23.

At step S13, the error correction decoding processing unit 23 performsthe error correction decoding processing such as LDPC, BCH, ReedSolomon, and convolutional code and outputs the data string after theerror correction decoding processing to the variable length packetprocessing unit 24.

At step S14, the variable length packet processing unit 24 performs thevariable length packet division processing according to whether theerror correction of the slot M and the slot M-1 of the data string afterthe error correction processing is successful or failed by using theerror correction information and the frame/slot information from theerror correction decoding processing unit 23. Meanwhile, the variablelength packet division processing is described later in detail withreference to FIG. 6 and the like.

At step S15, the variable length packet processing unit 24 outputs thepacket string obtained by the packet division to the data processingdevice 14 at the subsequent stage.

Next, the variable length packet division processing at step S14 in FIG.5 is described with reference to a flowchart in FIG. 6. Meanwhile, theexample in FIG. 6 is the example in which the packet division isperformed when decoding of both the slots M-1 and M is successful. Anumber in a balloon in FIG. 7 corresponds to a step number in FIG. 6,and FIG. 6 is illustrated with reference to FIG. 7 appropriately.

At step S31, the information analyzing unit 41 confirms whether theerror correction of the slot M is successful (A31 in FIG. 7). At stepS32, the packet dividing unit 43 obtains (at least one of) the TMCCinformation, the data length of the packet N-1, and the slot headerinformation of the slot M from the information analyzing unit 41.

Since a head pointer position may be obtained from any informationobtained at step S32, the packet dividing unit 43 divides the packet atthe head pointer position at step S33 (A33 in FIG. 7). At that time, thepacket dividing unit 43 supplies the packet division information to theinformation analyzing unit 41.

At step S34, the information analyzing unit 41 analyzes the data lengthof a current packet on the basis of the packet division information fromthe packet dividing unit 43 (A34 in FIG. 7). At step S35, theinformation analyzing unit 41 determines whether a next packet boundaryindicated by the data length of the current packet coincides with afinal pointer position of the TMCC information.

At step S35, in a case where it is determined that the next packetboundary coincides with the final pointer position of the TMCCinformation, the procedure shifts to step S36. At step S36, the packetdividing unit 43 divides the packet at the final pointer positionobtained from the information analyzing unit 41 (A36 in FIG. 7). At thattime, since the packet dividing unit 43 supplies the packet divisioninformation to the information analyzing unit 41, at step S37, theinformation analyzing unit 41 analyze the data length of the currentpacket by the packet division information from the packet dividing unit43 and thereafter finishes the variable length packet divisionprocessing.

On the other hand, in a case where it is determined that the next packetboundary does not coincide with the final pointer position of the TMCCinformation at step S35, the procedure shifts to step S38. At step S38,the packet dividing unit 43 divides the packet at the next packetboundary obtained from the information analyzing unit 41 (A38 in FIG.7). Thereafter, the procedure returns to step S34 and subsequentprocesses are repeated.

When the decoding of both the slots M-1 and M is successful, the packetdivision is performed as described above. The example in FIG. 6 is thevariable length packet division processing when the decoding of both theslot M-1 and slot M is successful.

On the other hand, due to failure in decoding of a certain block, anadjacent packet is conventionally invalidated regardless of presence orabsence of an error of the packet. As a result, “a packet without anerror contained” which may originally be used for decoding/playback orrecording is invalidated in some cases. Therefore, a suggestion not toinvalidate the packets not containing errors as much as possible isrequired.

In addition, the packet to be sent without invalidating the packet asmuch as possible might exceed a packet maximum size defined by thestandard and the like because there is an error in the data itselfindicating the data length of the packet, for example. Alternatively, ina case where a plurality of adjacent continuous packets is invalidateddue to failure in decoding a certain block, the invalidated packet (nullpacket) might exceed the packet maximum size defined by the standard orthe like. Alternatively, in a case of operation where an invalidatedpacket length is limited, there is a risk of exceeding that limit.

As described above, the packet exceeding the packet maximum size definedby the standard and the like might cause an overflow of the buffer ofthe data processing device 14 such as a decoder which receives areceiver output. Therefore, a method of always controlling the packetsize of the receiver output to be equal to or smaller than a valuedefined by the standard and the like is necessary.

Therefore, in the present technology, as for the packet including thedata of the block the decoding of which is failed, the packet is dividedwith a fixed packet length set to be the packet size upper limit.

Next, an example of performing the packet division when the decoding ofboth the slots M-1 and M is failed is described with reference to aflowchart in FIG. 8. FIG. 8 is the flowchart illustrating the variablelength packet division processing at step S14 in FIG. 5. Meanwhile, anumber in a balloon in FIG. 9 corresponds to a step number in FIG. 8,and FIG. 8 is illustrated with reference to FIG. 9 appropriately.

At step S51, the information analyzing unit 41 confirms failure in errorcorrection of the slot M (A51 in FIG. 9). At step S52, the packetdividing unit 43 obtains the data length of the TMCC information fromthe information analyzing unit 41.

Since the head pointer position may be obtained from the data lengthobtained at step S52, the packet dividing unit 43 performs the packetdivision at the head pointer position at step S53 (A53 in FIG. 9).

The packet length indicating unit 42 defines the packet length inadvance. Meanwhile, the defined packet length may also be updated bylearning to be described later or the like. At step S54, the packetdividing unit 43 divides the packet with the packet length defined bythe packet length indicating unit 42 (A54 in FIG. 9). At that time,overwriting packet division to be described later is performed.

At step S55, the packet dividing unit 43 determines whether a positionobtained by adding the defined packet length to the divided position isequal to or farther than the final pointer position of the TMCCinformation from the information analyzing unit 41. In a case where itis determined at step S55 that the position obtained by adding thedefined packet length to the divided position is not equal to or fartherthan the final pointer position of the TMCC information from theinformation analyzing unit 41, that is, this is before the final pointerposition, the procedure returns to step S54 and the subsequent processesare repeated.

In a case where it is determined at step S55 that the position obtainedby adding the defined packet length to the divided position is equal toor farther than the final pointer position of the TMCC information fromthe information analyzing unit 41, the procedure shifts to step S56. Atstep S56, the packet dividing unit 43 divides the packet at the finalpointer position (A56 in FIG. 9) to finish the variable length packetdivision processing.

When the decoding of both the slots M-1 and M is failed, the packetdivision is performed using the packet length defined as describedabove.

As described above, by dividing the packet with an inherent length(packet length) expected to be actually transmitted, it is possible tosend the packet which may not contain the error without invalidating thesame as much as possible. At that time, since the inherent length is setto the packet size upper limit, the packet size of the receiver outputmay always be controlled to be equal to or smaller than the valuedetermined by the standard or the like.

Next, an example of performing the packet division when the decoding ofthe slot M-1 is successful and the decoding of the slot M is failed isdescribed with reference to a flowchart in FIG. 10. FIG. 10 is theflowchart illustrating the variable length packet division processing atstep S14 in FIG. 5. Meanwhile, a number in a balloon in FIG. 11corresponds to a step number in FIG. 10, and FIG. 10 is illustrated withreference to FIG. 11 appropriately.

At step S71, the information analyzing unit 41 confirms the failure inerror correction of the slot M (A71 in FIG. 11). At step S72, the packetdividing unit 43 obtains at least one of the TMCC information and thedata length of the packet N-1 from the information analyzing unit 41.

Since the head pointer position may be obtained from the data lengthobtained at step S72, the packet dividing unit 43 divides the packet atthe head pointer position at step S73 (A73 in FIG. 11).

The packet length indicating unit 42 defines the packet length inadvance. At step S74, the packet dividing unit 43 performs the packetdivision with the packet length defined by the packet length indicatingunit 42 (A74 in FIG. 11). At that time, overwriting packet division tobe described later is performed.

At step S75, the packet dividing unit 43 determines whether a positionobtained by adding the defined packet length to the divided position isequal to or farther than the final pointer position of the TMCCinformation from the information analyzing unit 41. In a case where itis determined at step S75 that the position obtained by adding thedefined packet length to the divided position is not equal to or fartherthan the final pointer position of the TMCC information from theinformation analyzing unit 41, that is, this is before the final pointerposition, the procedure returns to step S74, and the subsequentprocesses are repeated.

In a case where it is determined at step S75 that the position obtainedby adding the defined packet length to the divided position is equal toor farther than the final pointer position of the TMCC information fromthe information analyzing unit 41, the procedure shifts to step S76. Atstep S76, the packet dividing unit 43 divides the packet at the finalpointer position (A76 in FIG. 11) to finish the variable length packetdivision processing.

When the decoding of the slot M-1 is successful and the decoding of theslot M is failed, the packet division is performed by using the definedpacket length as described above. In this example also, it is possibleto obtain an effect similar to that in the example in FIG. 8 by dividingthe packet with the inherent length (packet length) expected to beactually transmitted.

Next, an example in which the packet division is performed when thedecoding of the slot M-1 is successful and the decoding of the slot M isfailed as with FIG. 10, but the pointer information by the TMCC cannotbe used is described with reference to FIG. 12. FIG. 12 is a flowchartillustrating the variable length packet division processing at step S14in FIG. 5. Meanwhile, a number in a balloon in FIG. 13 corresponds to astep number in FIG. 12, and FIG. 12 is illustrated with reference toFIG. 13 appropriately.

At step S91, the information analyzing unit 41 confirms the failure inerror correction of the slot M (A91 in FIG. 13). At step S92, the packetdividing unit 43 obtains the data length of the packet N-1 from theinformation analyzing unit 41.

By calculating the data length obtained at step S92, the packet dividingunit 43 divides the packet at a position of a final byte of an (N-1)thpacket +1 at step S93, (A93 in FIG. 13).

The packet length indicating unit 42 defines the packet length bylearning and the like to be described later. At step S94, the packetdividing unit 43 performs the packet division with the packet lengthdefined by the packet length indicating unit 42 (A94 in FIG. 13). Atthat time, overwriting packet division to be described later isperformed.

At step S95, the packet dividing unit 43 determines whether a positionobtained by adding the defined packet length to the divided position isequal to or farther than a position indicated by the head pointer of anext block of which block error correction is successful. In a casewhere it is determined at step S95 that the position obtained by addingthe defined packet length to the divided position is not equal to orfarther than position indicated by the head pointer of the next blockthe block error correction of which is successful, that is, this isbefore the final pointer position, the procedure returns to step S94 andthe subsequent processes are repeated.

At step S95, in a case where it is determined that the position obtainedby adding the defined packet length to the divided position is equal toor farther than the position indicated by the head pointer of the nextblock the block error correction of which is successful, the procedureshifts to step S96. At step S96, the packet dividing unit 43 divides thepacket at the position indicated by the head pointer of the next blockthe block error correction of which is successful (in an example of A96in FIG. 13, a head of an (N+4)th packet) and finishes the variablelength packet division processing.

When the decoding of the slot M-1 is successful and the decoding of theslot M is failed, and the pointer information by the TMCC cannot beused, the packet division is performed as described above. In thisexample also, it is possible to obtain an effect similar to that in theexample in FIG. 8 by dividing the packet with the inherent length(packet length) expected to be actually transmitted.

Meanwhile, it is described above an example of dividing the packet witha fixed packet length set to the packet size upper limit as for thepacket including the data of the block the decoding of which is failed.In contrast, an example in which the data length stored in the header isanalyzed as for the packet including the data of the block the decodingof which is failed, and if the analyzed data length falls within adefined range of data lengths, probability of the packet may beconfirmed and the packet division is performed is next described withreference to FIG. 14.

FIG. 14 is a flowchart illustrating the variable length packet divisionprocessing at step S14 in FIG. 5. Meanwhile, the example in FIG. 14 isthe example in which the packet division is performed when the decodingof the slots M-1 is successful and the decoding of the slot M is failed.A number in a balloon in FIG. 15 corresponds to a step number in FIG.14, and FIG. 14 is illustrated with reference to FIG. 15 appropriately.

At step S111, the information analyzing unit 41 confirms the failure inerror correction of the slot M (A111 in FIG. 15). At step S112, thepacket dividing unit 43 obtains at least one of the TMCC information andthe data length of the packet N-1 from the information analyzing unit41.

Since the head pointer position may be obtained from the data lengthobtained at step S112, the packet dividing unit 43 divides the packet atthe head pointer position at step S113 (A113 in FIG. 15). At that time,the packet dividing unit 43 supplies the packet division information tothe information analyzing unit 41.

At step S114, the information analyzing unit 41 analyzes the data lengthof the current packet on the basis of the packet division informationfrom the packet dividing unit 43 (A114 in FIG. 15). At step S115, thepacket length indicating unit 42 obtains the data length of the currentpacket from the information analyzing unit 41.

The packet length indicating unit 42 defines a plurality of packetlengths (or a range of the packet lengths). At step S116, the packetlength indicating unit 42 determines whether the obtained data length ofthe current packet satisfies the defined range of the packet lengths(A116 in FIG. 15).

In a case where it is determined at step S116 that the data length ofthe current packet satisfies the defined range of the packet lengths,the procedure shifts to step S117 assuming that the packet is probable.At step S117, the packet dividing unit 43 determines whether the nextpacket boundary indicated by the data length of the current packet isequal to or farther than the final pointer position of the TMCCinformation from the information analyzing unit 41.

At step S117, in a case where it is determined that the next packetboundary indicated by the data length of the current packet is not equalto or farther than the final pointer position of the TMCC informationfrom the information analyzing unit 41, the procedure shifts to stepS118. At step S118, the packet dividing unit 43 next divides the packetat the packet boundary. Thereafter, the procedure returns to step S114and the subsequent processes are repeated.

At step S117, in a case where it is determined that the next packetboundary indicated by the data length of the current packet is equal toor farther than the final pointer position of the TMCC information fromthe information analyzing unit 41, the procedure shifts to step S119. Atstep 119, the packet dividing unit 43 divides the packet at the finalpointer position and finishes the variable length packet divisionprocessing.

On the other hand, in a case where it is determined at step S116 thatthe data length of the current packet does not satisfy the defined rangeof the packet lengths, the procedure shifts to step S120 assuming thatthe packet is not probable. At step S120, the packet dividing unit 43performs the packet division with the packet length defined by thepacket length indicating unit 42 (A120 in FIG. 15). At that time,overwriting packet division to be described later is performed.

At step S121, the packet dividing unit 43 determines whether theposition obtained by adding the defined packet length to the dividedposition is equal to or farther than the final pointer position of theTMCC information from the information analyzing unit 41. In a case whereit is determined at step S121 that the position obtained by adding thedefined packet length to the divided position is not equal to or fartherthan the final pointer position of the TMCC information from theinformation analyzing unit 41, that is, this is before the final pointerposition, the procedure returns to step S120 and the subsequentprocesses are repeated.

In a case where it is determined at step S121 that the position obtainedby adding the defined packet length to the divided position is equal toor farther than the final pointer position of the TMCC information fromthe information analyzing unit 41, the procedure returns to step S119.At step S119, the packet dividing unit 43 divides the packet at thefinal pointer position (A119 in FIG. 15) and finishes the variablelength packet division processing.

As described above, when the decoding of the slot M-1 is successful andthe decoding of the slot M is failed, as for the packet including thedata of the block the decoding of which is failed, if the data lengthstored in the header falls within the defined range of the data lengths,the data length of the current packet is used and the packet division isperformed. As a result, the packet including the block the decoding ofwhich is failed is also divided, so that it possible to send the packetwhich may not contain the error without invalidating the same as much aspossible.

On the other hand, in a case where the data length stored in the headerdoes not fall within the defined range of the data lengths, the packetdivision is performed with the defined packet length assuming that thepacket is not probable. As a result, as in the example in FIG. 8, bydividing the packet with the inherent length (packet length) expected tobe actually transmitted, it is possible to send the packet which may notcontain the error without invalidating the same as much as possible. Atthat time, since the inherent length is set to the packet size upperlimit, the packet size of the receiver output may always be controlledto be equal to or smaller than the value determined by the standard orthe like.

Next, the variable length packet division processing at step S14 in FIG.5 is described with reference to a flowchart in FIG. 16. Meanwhile, theexample in FIG. 16 is the example of performing the packet division byusing the data length of the current packet if the data length stored inthe header falls within the defined range of the data lengths as for thepacket including the data of the block the decoding of which is failedwhen the decoding of both the slots M-1 and M is failed. A number in aballoon in FIG. 17 corresponds to a step number in FIG. 16, and FIG. 16is illustrated with reference to FIG. 17 appropriately.

At step S141, the information analyzing unit 41 confirms the failure inerror correction of the slot M (A141 in FIG. 17). At step S142, thepacket dividing unit 43 obtains the data length of the TMCC informationfrom the information analyzing unit 41.

Since the head pointer position may be obtained from the data lengthobtained at step S142, the packet dividing unit 43 divides the packet atthe head pointer position at step S143 (A143 in FIG. 17).

At step S144, the information analyzing unit 41 analyzes the data lengthof the current packet on the basis of the packet division informationfrom the packet dividing unit 43 (A144 in FIG. 17). At step S145, thepacket length indicating unit 42 obtains the data length of the currentpacket from the information analyzing unit 41.

The packet length indicating unit 42 defines a plurality of packetlengths (or a range of the packet lengths). At step S146, the packetlength indicating unit 42 determines whether the obtained data length ofthe current packet satisfies the defined range of the packet lengths(A146 in FIG. 17).

In a case where it is determined at step S146 that the data length ofthe current packet satisfies the defined range of the packet lengths,the procedure shifts to step S147. At step S147, the packet dividingunit 43 determines whether the next packet boundary indicated by thedata length of the current packet is equal to or farther than the finalpointer position of the TMCC information from the information analyzingunit 41.

At step S147, in a case where it is determined that the next packetboundary indicated by the data length of the current packet is not equalto or farther than the final pointer position of the TMCC informationfrom the information analyzing unit 41, the procedure shifts to stepS148. At step S148, the packet dividing unit 43 next divides the packetat the packet boundary. Thereafter, the procedure returns to step S144and the subsequent processes are repeated.

At step S147, in a case where it is determined that the next packetboundary indicated by the data length of the current packet is equal toor farther than the final pointer position of the TMCC information fromthe information analyzing unit 41, the procedure shifts to step S149. Atstep 149, the packet dividing unit 43 divides the packet at the finalpointer position and finishes the variable length packet divisionprocessing.

On the other hand, in a case where it is determined at step S146 thatthe data length of the current packet does not satisfy the defined rangeof the packet lengths, the procedure shifts to step S150. At step S150,the packet dividing unit 43 performs the packet division with the packetlength defined by the packet length indicating unit 42 (A150 in FIG.17). At that time, overwriting packet division to be described later isperformed.

At step S151, the packet dividing unit 43 determines whether theposition obtained by adding the defined packet length to the dividedposition is equal to or farther than the final pointer position of theTMCC information from the information analyzing unit 41. In a case whereit is determined at step S151 that the position obtained by adding thedefined packet length to the divided position is not equal to or fartherthan the final pointer position of the TMCC information from theinformation analyzing unit 41, that is, this is before the final pointerposition, the procedure returns to step S150 and the subsequentprocesses are repeated.

In a case where it is determined at step S151 that the position obtainedby adding the defined packet length to the divided position is equal toor farther than the final pointer position of the TMCC information fromthe information analyzing unit 41, the procedure shifts to step S149. Atstep S149, the packet dividing unit 43 divides the packet at the finalpointer position (A149 in FIG. 17) and finishes the variable lengthpacket division processing.

As described above, when the decoding of the slots M-1 and M is failed,as for the packet including the data of the block the decoding of whichis failed also, if the data length stored in the header falls within thedefined range of the data lengths, the data length of the current packetis used and the packet division is performed. On the other hand, in acase where the data length stored in the header does not fall within thedefined range of the data length, it is determined that the packet isnot correct, and the packet division is performed with the definedpacket length. As a result, the effect similar to that in the example inFIG. 14 is obtained.

<Overwriting Packet Division>

Meanwhile, processing when overwriting division is performed in a casewhere the packet division is performed with the packet length defined bythe packet length indicating unit 42 (for example, step S54 in FIG. 8,step S74 in FIG. 10, step S94 in FIG. 12, step S120 in FIG. 14, or stepS150 in FIG. 16) in the description above is described.

In the above-described processing, in a case of performing the packetdivision using the data length information of the block the decoding ofwhich might be failed, or the packet division using the packet lengthobtained from the packet length indicating unit 42, the packet headerinformation included in the data might be wrong.

In this case, as illustrated in FIG. 18, a data string of a site newlycorresponding to the TLV packet header may be (overwritten) corrected soas to correspond to the TLV packet header such that the packet has aformat of the TLV packet.

In an example in FIG. 18, the data string by the packet divisionaccording to the present proposal is illustrated under the actuallytransmitted data string. In the present proposal, the header of thepacket N-1 may include different data originally, but this isoverwritten with one or more of a synchronous byte, predetermined typeinformation, and a data length at the time of division. The same appliesto the header of the packet N.

Also, another example of a case where the packet division using the datalength information of the block the decoding of which might be failed orthe packet division using the packet length obtained from the packetlength indicating unit 42 is performed in the above-described processingis described with reference to FIGS. 19 and 20.

In the above-described case, when the number of bytes from the dividedposition to the divided position by the final pointer (assumed to be apseudo packet N) is equal to or smaller than a minimum value (four bytesin the case of TLV) of the packet length defined by the standard,processing of preventing output of this pseudo packet is performed.

In the example in FIG. 19, the data string by the packet divisionaccording to the present proposal is illustrated under the actuallytransmitted data string. At the time of the packet division according tothe present proposal, as described above with reference to FIG. 18, theheader of the packet N-1 is overwritten with one or more of thesynchronous byte, the predetermined type information, and the datalength at the time of division.

Next, as for the pseudo packet N, the size of which is equal to orsmaller than four bytes and there is standard mismatch, so that a validflag of the data is negated as an overwriting operation example 1.

Alternatively, as an overwriting operation example 2, the length of thepacket N-1 is adjusted, the header is added to the pseudo packet N, andthe length is satisfied such that both the packet N-1 and the pseudopacket N have a size matching to the standard. Meanwhile, in this case,a data string of a site newly corresponding to the TLV packet header maybe corrected so as to correspond to the TLV packet header such that aformat of the TLV packet is newly obtained such that the packet has theformat of the TLV packet.

Furthermore, in the above-described case, it is possible to add anindicator indicating the packet head as illustrated in FIG. 20 to thedata string with a predetermined protocol.

In the example of FIG. 20, the indicator indicating the packet head isadded to the head of the packet N-1 on which the division processing isperformed with the defined length, and further, the indicator indicatingthe packet head is added to the head of the packet N on which thedivision processing is performed with the defined length.

Meanwhile, this operation may be performed together with the operation 1or 2 described above with reference to FIG. 19. That is, operation ofpreventing the divided packet from having the minimum value (four bytesin the case of TLV) or smaller of the packet length determined by thestandard (operation 1 or 2 in FIG. 19) is performed, and the indicatorindicating the packet head is added to the data string by thepredetermined protocol. This makes it unnecessary to modify contents ofthe packet.

<Setting Method 1 of Defined Value of Packet Length>

Meanwhile, as described above, in a case where the variable lengthpacket is used, a general broadcasting company might perform the packetdivision with the maximum packet length defined by the standard or thefixed packet length close thereto in order to maximize a transmissionrate and transmit the same.

In contrast, the fixed packet length cannot be known in advance, andthis might be changed depending on sending setting and the like of thebroadcasting company.

Therefore, in a case of performing the packet division with the packetlength defined by the packet length indicating unit 42 (for example,step S54 in FIG. 8, step S74 in FIG. 10, step S94 in FIG. 12, step S120in FIG. 14, or step S150 in FIG. 16), as illustrated in FIG. 21, thepacket length indicating unit 42 monitors a packet length L of thepacket divided in a slot error correction of which is successful in acase where an initial value of the defined value is Lb, thereby learningthe defined value. That is, for example, when the same value Lacontinues in the packets as actual performance, the value (La) is made anew defined value. Then, the packet length indicating unit 42 indicatesthe packet length with a new defined value.

Meanwhile, the learned value La may be individually held according tothe type of packet (NTP packet, compressed packet, uncompressed packetand the like).

<Setting Method 2 of Defined Value of Packet Length>

Also, as described above, in a case where the variable length packet isused, the general broadcasting company might perform the packet divisionusing the maximum packet length defined by the standard or a range ofthe packet lengths close thereto in order to maximize the transmissionrate and transmit the same.

On the other hand, the packet length range (or sent packet length)cannot be known in advance, and this might be changed depending on thesending setting and the like of the broadcasting company.

Therefore, in a case where the range of the packet lengths is used (forexample, step S116 in FIG. 14 or step S146 in FIG. 16), the packetlength indicating unit 42 monitors the packet length L of the packetdivided in the slot the error correction of which is successful, therebyleaning a range Ra which the packet length may take, for example. Then,the packet length indicating unit 42 uses the learned Ra to determinecorrectness of the packet.

In an example in FIG. 22, the initial value of the packet length rangeis Ra=4 to 1500; however, the packet length indicating unit 42 monitorsthe packet lengths (L=1450, L=1400, L=1500, and L=1480) of the packetsdivided in the slot the error correction of which is successful, therebylearning that Ra′=1400 to 1500. Then, the packet length indicating unit42 determines the probability of the packet by performing the datalength analysis and comparison (1400<L and L<1500).

As described above, according to the present technology, as for thepacket including the data of the block the decoding of which is failed,the packet is divided with the fixed packet length.

As a result, by dividing the packet with the inherent length expected tobe actually transmitted, it is possible to send the packet that may notcontain an error without invalidating the same as much as possible.

In addition, by setting the inherent length to the upper limit of thepacket size, the packet size of the receiver output may always becontrolled to be equal to or smaller than the value determined by thestandard or the like.

Also, according to the present technology, as for the packet includingthe data of the block the decoding of which is failed, the data lengthstored in the header is analyzed, and if the analyzed data length fallswithin a separately set range of the data lengths, the packet divisionis performed assuming that the probability of the packet may beconfirmed.

As a result, the packet including the block the decoding of which isfailed is also divided, so that it possible to send the packet which maynot contain the error without invalidating the same as much as possible.

Furthermore, according to the present technology, in a case where theanalyzed data length takes a value outside the set range, the packet maybe divided with the packet length obtained by dividing with the fixedpacket length on the basis of the next byte of the final byte of thefinal packet the packet division of which is normally performed.

As a result, as for the packet considered to have the error in the datalength, by dividing the packet with the inherent length expected to betransmitted, it is possible to send the packet which may not contain theerror without invalidating the same as much as possible. Also, bysetting the inherent length to the upper limit of the packet size, thepacket size of the receiver output may always be controlled to be equalto or smaller than the value determined by the standard or the like.

2. Second Embodiment (Cable Retransmission) <Configuration Example ofCommunicating System of Present Technology>

FIG. 23 is a view illustrating a configuration example of a cableretransmitting system as a communicating system to which the presenttechnology is applied.

In the example in FIG. 23, a cable retransmitting system 201 includes atransmitting device 11 which divides a broadcast signal of advancedbroadband digital broadcasting into packet units and multiplexing themto transmit, a cable retransmitting device 211 which receives thebroadcast signal divided into the packet units to be multiplexed,performs NIT conversion and TLV multiplexing, and modulates by a cablemethod to retransmit, and a receiving device 212 which receives thesignal modulated by the cable method.

In the cable retransmitting system 201, for example, when a TLV packetbeing a variable length packet transmitted by the transmitting device 11is demodulated and obtained, cable modulation for making the same asignal of a cable method (that is, a divided TLV packet or a BB Frame)is performed.

Meanwhile, at the time of demodulation, it is also possible to output asthe signal of the cable method as with the case of TS, but whendemodulating by the receiving device 212 in FIG. 23, the original TLVpacket is taken out from the cable method to be output.

<Configuration Example of Cable Retransmitting Device and ReceivingDevice>

FIG. 24 is a block diagram illustrating a configuration example of thecable retransmitting device and the receiving device in FIG. 23.

In the example in FIG. 24, a data processing device 213 including adecoder at a subsequent stage and the like is configured at a subsequentstage of the receiving device 212, and data subjected to signalprocessing by the receiving device 212 is output to the data processingdevice 213.

The cable retransmitting device 211 includes an antenna 221, a satellitetuner 222, a converter/multiplexer 223, a cable modulator 224, and atransmitting unit 225.

The satellite tuner 222 performs RF processing on a broadcast signal ofsatellite broadcasting and the like, for example, received by theantenna 221, and outputs the signal after the RF processing to theconverter/multiplexer 223. The converter/multiplexer 223 performs NITconversion, TS/TLV multiplexing and the like and outputs to the cablemodulator 224.

The cable modulator 224 modulates again by the cable method (such asISDB-C or J.382) and outputs the signal modulated to the cable method(that is, the divided TLV packet in the case of ISDB-C, or the BB Framein the case of J.382) to the transmitting unit 225. The transmittingunit 225 transmits the signal modulated to the cable method to thereceiving device 212.

The receiving device 212 includes a tuner unit 241, a demodulationprocessing unit 242, an error correction decoding processing unit 243,and a variable length packet processing unit 244.

The tuner unit 241 performs the RF processing on the signal modulated tothe cable method from the cable retransmitting device 211, and outputsthe signal after the RF processing to the demodulation processing unit242. The demodulation processing unit 242 performs demodulationprocessing on the signal after the RF processing and outputs digitalsignals 0 and 1 as a result of the demodulation to the error correctiondecoding processing unit 243.

The error correction decoding processing unit 243 performs errorcorrection decoding processing such as LDPC, BCH, Reed Solomon, andconvolutional code, and outputs a data string after the error correctiondecoding processing to the variable length packet processing unit 244.At that time, the error correction decoding processing unit 243 alsosupplies error correction information to the variable length packetprocessing unit 244.

The variable length packet processing unit 244 performs variable lengthpacket division processing according to whether error correction of aunit of processing (BB Frame or divided TLV packet) M of the data stringafter the error correction processing is successful or failed by usingthe error correction information from the error correction decodingprocessing unit 243. The variable length packet processing unit 244outputs a packet string obtained by packet division to the dataprocessing device 213 at a subsequent stage.

<Configuration Example of Variable Length Packet Processing Unit>

FIG. 25 is a block diagram illustrating a configuration example of thevariable length packet processing unit.

The variable length packet processing unit 244 includes an informationanalyzing unit 251, a packet length indicating unit 252, and a packetdividing unit 253.

The data string from the error correction decoding processing unit 243is input to the information analyzing unit 251 and the packet dividingunit 253. The error correction information from the error correctiondecoding processing unit 243 is input to the packet dividing unit 253.

The information analyzing unit 251 analyzes the data string and suppliesdata length information to the packet length indicating unit 252 and thepacket dividing unit 253.

The packet length indicating unit 252 defines a packet length inadvance, and indicates the defined packet length to the packet dividingunit 253. Meanwhile, the packet length may be defined to be, forexample, a packet size upper limit provided in terms of standard andoperation. Also, as described above with reference to FIGS. 21 and 22,for example, the packet length may be updated on the basis of a resultof learning the packet length obtained by division processing.

The packet dividing unit 253 performs the packet division on the basisof at least one of the information (data length information) from theinformation analyzing unit 251 and the packet length indicated by thepacket length indicating unit 252. Regarding the packet length,especially, the packet dividing unit 253 performs the packet division onthe basis of the packet length obtained from the information (datalength information) from the information analyzing unit 251 or thepacket length indicated by the packet length indicating unit 252. Thepacket string obtained by the division by the packet dividing unit 253is output to the data processing device 213 at a subsequent stage. Thepacket dividing unit 253 outputs packet division information beinginformation of a position of division to the information analyzing unit251. Meanwhile, the packet dividing unit 253 includes a buffer.

<BB Frame Configuration Example>

Next, a method of detecting TLV packet boundary information in the BBFrame is described with reference to FIG. 26. In a case of J.382, theTLV packet is subjected to the cable modulation by the cableretransmitting device 211 to be modulated to a GSE packet, and further,the GSE packet is modulated to the BB Frame to be transmitted.

In an example in FIG. 26, a BB Frame configuration is illustrated. TheBB Frame includes a BB (Frame) Header, a data field, and padding.

The BB (Frame) Header includes 2-byte MATYPE, 2-byte ISSY1, 2-byte DFL,1-byte ISSY2, 2-byte SYNCD, and 1-byte CRC, in which a position of thedata field of the BB Frame is known from the DFL, and a head of the GSEpacket is known from the SYNCD.

The GSE packet includes a GSE header and data, and the GSE headerincludes a GSE packet length.

The TLV packet includes a TLV header and data.

In FIG. 26, for the purpose of description, balloons indicating numbersare illustrated. The packet boundary information may be detected fromtwo types of information indicated by balloons 1 and 2 in FIG. 26.

1 indicates a head TLV indication by the SYNCD of the BB (Frame) Header.

2 indicates TLV division information by the GSE packet header.

Herein, 1 and 2 may be detected from the data string.

That is, by using the information of the BB (Frame) Header and a GSEheader length, it is possible to divide into GSE packets. Also, sinceone or a plurality of GSE packet data=TLV packet data, the TLV headermay replace by analyzing the GSE packet header.

As described above, in a case of the example in FIG. 26, the presenttechnology may be applied to error processing when outputting the GSEpacket from the BB Frame.

<Configuration Example of Divided TLV Packet>

Next, with reference to FIG. 27, a method of detecting the TLV packetboundary information in the divided TLV packet is described. In the caseof ISDB-C, the TLV packet is subjected to the cable modulation by thecable retransmitting device 211 to be transmitted as the divided TLVpacket.

In the example in FIG. 27, a divided TLV packet configuration of anerror correction unit is illustrated. The divided TLV packet includesdivided TLV packets #0 to #N. The divided TLV packet #0 includes a3-byte divided TLV packet header and a 185-byte payload part including apart of a TLV packet N-1 and a part of a TLV packet N. Meanwhile, thepayload part of the divided TLV packet #1 includes a part of the TLVpacket N, and the payload part of the divided TLV packet #2 includes apart of the TLV packet N and a part of a TLV packet N+1.

The divided TLV packet header includes an 8-bit synchronous byte, a1-bit transport error indicator, a 1-bit TLV packet start indicator, a1-bit ‘0’, and a 13-bit PID.

If the TLV packet start indicator of the divided TLV packet headerindicates that there is a TLV head, the payload part includes an 8-bithead TLV indication, so that the TLV head position may be known.

In FIG. 27, for the purpose of illustration, balloons indicating numbersare illustrated. In the divided TLV packet, the packet boundaryinformation may be detected from two types of information indicated byballoon 1 and balloon 2 in FIG. 27.

1 indicates the head TLV indication by a slot divided TLV packet header.

2 indicates packet length cumulative information of the packet header.

Herein, 1 and 2 may be detected from the data string, and robustness ofthe information becomes higher in descending order of 1 and 2.

As described above, in the case of the example in FIG. 27, the presenttechnology may be applied to error processing when outputting theoriginal TLV packet from the divided TLV packet.

<Processing Example of Receiving Device>

Next, reception processing by the receiving device 212 is described withreference to a flowchart in FIG. 28.

At step S211, the tuner unit 241 performs the RF processing on thesignal modulated to the cable method from the cable retransmittingdevice 211 and outputs the signal after the RF processing to thedemodulation processing unit 242. At step S212, the demodulationprocessing unit 242 performs the demodulation processing on the signalafter the RF processing and outputs the digital signals 0 and 1 obtainedas a result of the demodulation to the error correction decodingprocessing unit 243.

At step S213, the error correction decoding processing unit 243 performsthe error correction decoding processing such as LDPC, BCH, ReedSolomon, and convolutional code, and outputs the data string after theerror correction decoding processing to the variable length packetprocessing unit 244.

At step S214, the variable length packet processing unit 244 performsthe variable length packet division processing according to whether theerror correction of the data string after the error correctionprocessing is successful or failed by using the error correctioninformation from the error correction decoding processing unit 243.Meanwhile, the variable length packet division processing is describedlater in detail with reference to FIG. 29 and subsequent drawings.

At step S215, the variable length packet processing unit 244 outputs thepacket string obtained by the packet division to the data processingdevice 213 at the subsequent stage.

<Case of BB Frame (J.382)>

Next, the variable length packet division processing at step S214 inFIG. 28 is described with reference to a flowchart in FIG. 29.Meanwhile, the example in FIG. 29 is an example in which (GSE) packetdivision is performed upon successful decoding (error correction) of theBB Frame. A number in a balloon in FIG. 30 corresponds to a step numberin FIG. 29, and FIG. 29 is illustrated with reference to FIG. 30appropriately.

At step S231, the information analyzing unit 251 confirms success of theerror correction of the BB Frame M (A231 in FIG. 30). At step S232, thepacket dividing unit 253 obtains (at least one of) the data length ofthe packet N-1 and the SYNCD information of the BB Frame M from theinformation analyzing unit 251.

Since a head pointer position may be known from any information obtainedat step S232, the packet dividing unit 253 divides the packet at thehead pointer position at step S233 (A233 in FIG. 30). At that time, thepacket dividing unit 253 supplies the packet division information to theinformation analyzing unit 251.

At step S234, the information analyzing unit 251 analyzes the datalength of a current packet on the basis of the packet divisioninformation from the packet dividing unit 253 (A234 in FIG. 30).

At step S235, the packet dividing unit 253 divides the packet at a nextpacket boundary obtained from the information analyzing unit 251 (A235in FIG. 30).

At step S236, the packet dividing unit 253 determines whether the BBFrame is stepped over by division. In a case where it is determined atstep S236 that the BB Frame is stepped over, the procedure returns tostep S231, and the subsequent processes are repeated. Also, in a casewhere it is determined at step S236 that the BB Frame is not steppedover, the procedure returns to step S234 and the subsequent processesare repeated.

Next, an example in which the packet division is performed when thedecoding of the BB Frame M is failed is described with reference to aflowchart in FIG. 31. FIG. 31 is the flowchart illustrating the variablelength packet division processing at step S214 in FIG. 28. Meanwhile, anumber in a balloon in FIG. 32 corresponds to a step number in FIG. 31,and FIG. 31 is illustrated with reference to FIG. 32 appropriately.

At step S251, the information analyzing unit 251 confirms the failure inthe error correction of the BB Frame M (A251 in FIG. 32). At step S252,the packet dividing unit 253 determines a head position of an Nth packetby using a data length of an (N-1)th packet to divide (A252 in FIG. 32).

The packet length indicating unit 252 defines the packet length. At stepS253, the packet dividing unit 253 performs the packet division with thelength defined as the data length of the Nth packet by the packet lengthindicating unit 252 (A253 in FIG. 32). Meanwhile, the length at thattime has following patterns.

-   -   The data length is used as it is as the length of the packet.    -   The data length is ignored and a fixed length is used as a        packet length A (for example, a value likely to be used in        operation (1500 bytes in a case of cable retransmission of        advanced BS broadcasting) is considered).    -   In a case where the data length is equal to or longer than a        certain value X or equal to or shorter than a certain value Y, A        is used. Alternatively, X or Y is used.    -   As described above with reference to FIG. 21 or FIG. 22, a        received packet is learned for a certain period, and the data        length obtained by learning is used.

Meanwhile, at that time also, overwriting packet division describedabove with reference to FIGS. 18 to 20 may be performed.

At step S254, the packet dividing unit 253 determines whether a positionindicated by the data length steps over a current BB Frame. In a casewhere it is determined at step S254 that the position indicated by thedata length steps over the current BB Frame (A254 in FIG. 32), theprocedure returns to step S251, and the subsequent processes arerepeated.

On the other hand, in a case where it is determined at step S254 thatthe position indicated by the data length does not step over the currentBB Frame, the procedure returns to step S253, and the subsequentprocesses are repeated.

That is, in a case where the failure in the error correction of the BBFrame M is confirmed, this procedure is repeated. On the other hand, ina case where the success of the error correction of the BB Frame M isconfirmed, the above-described procedure in FIG. 29 is performed.

<Case of Divided TLV Packet (ISDB-C)>

Next, the variable length packet division processing at step S214 inFIG. 28 is described with reference to a flowchart in FIG. 33.Meanwhile, an example in FIG. 33 is the example in which the packetdivision is performed when the decoding (error correction) of thedivided TLV packet is successful. A number in a balloon in FIG. 34corresponds to a step number in FIG. 33, and FIG. 33 is illustrated withreference to FIG. 34 appropriately.

At step S271, the information analyzing unit 251 confirms the success ofthe error correction of the divided TLV packet M (A271 in FIG. 34). Atstep S272, the packet dividing unit 253 obtains (at least one of) thedata length of the packet N-1 and head TLV indication information of thedivided TLV packet M from the information analyzing unit 251.

Since the head pointer position may be known from any informationobtained at step S272, the packet dividing unit 253 divides the packetat the head pointer position at step S273 (A273 in FIG. 34). At thattime, the packet dividing unit 253 supplies the packet divisioninformation to the information analyzing unit 251.

At step S274, the information analyzing unit 251 analyzes the datalength of the current packet on the basis of the packet divisioninformation from the packet dividing unit 253 (A274 in FIG. 34).

At step S275, the packet dividing unit 253 divides the packet at thenext packet boundary obtained from the information analyzing unit 251(A275 in FIG. 34).

At step S276, the packet dividing unit 253 determines whether a dividedTLV packet boundary is stepped over by division. In a case where it isdetermined at step S276 that the divided TLV packet boundary is steppedover, the procedure returns to step S271 and the subsequent processesare repeated. Also, in a case where it is determined at step S276 thatthe divided TLV packet boundary is not stepped over, the procedurereturns to step S274 and the subsequent processes are repeated.

Next, an example of performing the packet division when the decoding ofthe divided TLV packet M is failed is described with reference to aflowchart in FIG. 35. FIG. 35 is the flowchart illustrating the variablelength packet division processing at step S214 in FIG. 28. Meanwhile, anumber in a balloon in FIG. 36 corresponds to a step number in FIG. 35,and FIG. 35 is illustrated with reference to FIG. 36 appropriately.

At step S291, the information analyzing unit 251 confirms the failure inthe error correction of the divided TLV packet M (A291 in FIG. 36). Atstep S292, the packet dividing unit 253 determines the head position ofthe Nth packet by using the data length of the (N-1)th packet (A292 inFIG. 36).

The packet length indicating unit 252 defines the packet length. At stepS293, the packet dividing unit 253 performs the packet division with thelength defined as the data length of the Nth packet by the packet lengthindicating unit 252 (A293 in FIG. 36). Meanwhile, the length at thattime has following patterns.

-   -   The data length is used as it is as the length of the packet.    -   The data length is ignored and a fixed length is used as a        packet length A (for example, a value likely to be used in        operation (1500 bytes in a case of cable retransmission of        advanced BS broadcasting) is considered).    -   In a case where the data length is equal to or longer than a        certain value X or equal to or shorter than a certain value Y, A        is used. Alternatively, X or Y is used.    -   As described above with reference to FIG. 21 or FIG. 22, a        received packet is learned for a certain period, and the data        length obtained by learning is used.

Meanwhile, at that time also, overwriting packet division describedabove with reference to FIGS. 18 to 20 may be performed.

At step S294, the packet dividing unit 253 determines whether theposition indicated by the data length steps over the current divided TLVpacket. In a case where it is determined at step S294 that the positionindicated by the data length steps over the current TLV packet (A294 inFIG. 36), the procedure returns to step S291 and the subsequentprocesses are repeated.

On the other hand, in a case where it is determined at step S294 thatthe position indicated by the data length does not step over the dividedTLV packet, the procedure returns to step S293 and the subsequentprocesses are repeated.

That is, in a case where the failure in the error correction of thedivided TLV packet M is confirmed, this procedure is repeated. On theother hand, in a case where the success of the error correction of thedivided TLV packet M is confirmed, the above-described procedure in FIG.33 is performed.

<Comparison Between Advanced BS Broadcasting and Cable Retransmission>

FIG. 37 is a view illustrating an applicable range of the presenttechnology in the advanced BS broadcasting of the first embodiment andthe cable retransmission (ISDB-C, J.382) of the second embodiment.

A packet break position indication by the TMCC information (errortolerance: strong) indicates the first and last packet boundaries in theslot from the TMCC information (error tolerance is strong) in a case ofadvanced BS (slot->TLV). However, in the cable retransmissionISDB-C(divided TLV->TLV) and the cable retransmission J.382 (BBFrame->GSE), this is not applied because there is no TMCC information.

The packet break position indication by the header (error tolerance:medium) indicates the first packet boundary in the slot from the slotheader (error tolerance is medium) in a case of advanced BS (slot->TLV).In a case of the cable retransmission ISDB-C (divided TLV->TLV), a headpacket boundary in the divided TLV is indicated using the divided TLVheader and the payload. In a case of the cable retransmission J.382 (BBFrame->GSE), the first packet boundary in the BB Frame is indicated.

In the case of the advanced BS (slot->TLV), the packet length indication(error tolerance: medium) indicates the packet length of the TLV of theTLV header. In the case of the cable retransmission ISDB-C(dividedTLV->TLV), the packet length of the TLV of the TLV header is indicated.In the case of the cable retransmission J.382 (BB Frame->GSE), thepacket length of the GSE in the GSE header is indicated.

Meanwhile, in the case of the cable retransmission J.382 (GSE->TLV),only the header is replaced, so that there is no special errorprocessing function.

As described above, by using the header information and the packetlength, it is possible to break the packet at the packet boundary whichis correct with probability as high as possible when an error occurseven in the case of the cable retransmission.

That is, in the case of the cable retransmission, it is possible toperform processing similar to that in the case where the TMCCinformation cannot be used in the advanced BS broadcasting.

As described above, according to the present technology, as for thepacket including the data of the block the decoding of which is failed,the packet is divided with the fixed packet length.

As a result, by dividing the packet with the inherent length expected tobe actually transmitted, it is possible to send the packet that may notcontain an error without invalidating the same as much as possible.

In addition, by setting the inherent length to the upper limit of thepacket size, the packet size of the receiver output may always becontrolled to be equal to or smaller than the value determined by thestandard or the like.

Also, according to the present technology, as for the packet includingthe data of the block the decoding of which is failed, the data lengthstored in the header is analyzed, and if the analyzed data length fallswithin a separately set range of the data lengths, the packet divisionis performed assuming that the probability of the packet may beconfirmed.

As a result, the packet including the block the decoding of which isfailed is also divided, so that it possible to send the packet which maynot contain the error without invalidating the same as much as possible.

Furthermore, according to the present technology, in a case where theanalyzed data length takes a value outside the set range, the packet maybe divided with the packet length obtained by dividing with the fixedpacket length on the basis of the next byte of the final byte of thefinal packet the packet division of which is normally performed.

As a result, as for the packet considered to have the error in the datalength, by dividing the packet with the inherent length expected to betransmitted, it is possible to send the packet which may not contain theerror without invalidating the same as much as possible. Also, bysetting the inherent length to the upper limit of the packet size, thepacket size of the receiver output may always be controlled to be equalto or smaller than the value determined by the standard or the like.

3. Third Embodiment (Personal Computer) <Personal Computer>

A series of processes described above may be executed by hardware or bysoftware. In a case where a series of processes is performed by thesoftware, a program which forms the software is installed on a computer.Herein, the computer includes a computer embedded in dedicated hardware,a general-purpose personal computer capable of executing variousfunctions by various programs installed, and the like.

FIG. 38 is a block diagram illustrating a configuration example ofhardware of a personal computer which executes the above-describedseries of processes by a program.

In a personal computer 500, a central processing unit (CPU) 501, a readonly memory (ROM) 502, and a random-access memory (RAM) 503 areconnected to one another through a bus 504.

An input/output interface 505 is further connected to the bus 504. Aninput unit 506, an output unit 507, a storage unit 508, a communicationunit 509, and a drive 510 are connected to the input/output interface505.

The input unit 506 includes a keyboard, a mouse, a microphone, and thelike. The output unit 507 includes a display, a speaker and the like.The storage unit 508 includes a hard disk, a non-volatile memory and thelike. The communication unit 509 includes a network interface and thelike. The drive 510 drives a removable medium 511 such as a magneticdisk, an optical disk, a magnetooptical disk, or a semiconductor memory.

In the personal computer 500 configured in the above-described manner,the CPU 501 loads the program stored in the storage unit 508, forexample, on the RAM 503 through the input/output interface 505 and thebus 504 to execute. As a result, the series of processes described aboveis performed.

The program executed by the computer (CPU 501) may be recorded on theremovable medium 511 to be provided. The removable medium 511 is, forexample, a package medium including a magnetic disk (including aflexible disk), an optical disk (a compact disc-read only memory(CD-ROM), a digital versatile disc (DVD) and the like), a magnetoopticaldisk, a semiconductor memory, or the like. Also, the program may beprovided by means of a wired or wireless transmission medium such as alocal area network, the Internet, and digital broadcasting.

In the computer, the program may be installed on the storage unit 508through the input/output interface 505 by mounting the removable medium511 on the drive 510. Also, the program may be received by thecommunication unit 509 through the wired or wireless transmission mediumto be installed on the storage unit 508. In addition, the program may beinstalled in advance on the ROM 502 and the storage unit 508.

Meanwhile, the program executed by the computer may be the program ofwhich processes are performed in chronological order in the orderdescribed in this specification or may be the program of which processesare performed in parallel or at required stage such as when a call isissued.

Also, in this specification, a step of describing the program recordedin the recording medium includes not only the processes performed inchronological order in the described order but also the processesexecuted in parallel or individually which are not necessarily performedin chronological order.

Also, in this specification, a system means an entire apparatusincluding a plurality of devices (apparatuses).

Meanwhile, the embodiment in the present disclosure is not limited tothe above-described embodiments; various modifications may be madewithout departing from the scope of the present disclosure.

For example, the present disclosure may be configured as cloud computingin which one function is shared by a plurality of devices through anetwork for processing in cooperation.

It is also possible to divide the configuration described above as onedevice (or processor) into a plurality of devices (or processors). Otherway round, it is also possible to put the configurations described aboveas a plurality of devices (or processors) together as one device (orprocessor). Also, of course, it is possible that a configuration otherthan the above-described one is added to the configuration of eachdevice (or each processor). Furthermore, it is also possible that a partof the configuration of a certain device (or processor) is included inthe configuration of another device (or another processor) as long as aconfiguration and operation as an entire system are substantially thesame. That is, the present technology is not limited to theabove-described embodiments and various modifications may be madewithout departing from the spirit of the present technology.

Although the preferred embodiments of the present disclosure aredescribed above in detail with reference to the attached drawings, thedisclosure is not limited to such examples. It is clear that one ofordinary skill in the field of the technology to which the presentdisclosure belongs may conceive of various modifications and correctionswithin the scope of the technical idea recited in claims and it isunderstood that they also naturally belong to the technical scope of thepresent disclosure.

Meanwhile, the present technology may also have followingconfigurations.

(1) A receiving device provided with:

an information analyzing unit which analyzes packet informationregarding a packet from a transmitted multiplexed stream;

a packet length indicating unit which defines a packet length; and

a packet dividing unit which divides the multiplexed stream into packetsby using at least one of the packet information analyzed by theinformation analyzing unit and the packet length defined by the packetlength indicating unit.

(2) The receiving device according to (1) described above,

in which the packet dividing unit divides the multiplexed stream intopackets by using the packet length in the packet information analyzed bythe information analyzing unit or the packet length indicating thepacket length defined by the packet length indicating unit according toa comparison result between the packet length in the packet informationanalyzed by the information analyzing unit and a range of the packetlength defined by the packet length indicating unit.

(3) The receiving device according to (2) described above,

in which the packet dividing unit divides the multiplexed stream intopackets by using the packet length in the packet information in a casewhere it is determined that the packet length in the packet informationanalyzed by the information analyzing unit falls within the range of thepacket length defined by the packet length indicating unit.

(4) The receiving device according to (2) or (3) described above,

in which the packet dividing unit divides the multiplexed stream intopackets by using the packet length defined by the packet lengthindicating unit in a case where it is determined that the packet lengthin the packet information analyzed by the information analyzing unit isout of the range of the packet length defined by the packet lengthindicating unit.

(5) The receiving device according to any one of (1) to (4) describedabove,

in which, in a case where the packet divided on the basis of the packetlength defined by the packet length indicating unit is the packet havinga non-standard short packet length, the packet dividing unit adjusts adivided position with an immediately preceding packet length orinvalidates the packet having the short packet length.

(6) The receiving device according to any one of (1) to (5) describedabove,

in which the packet dividing unit rewrites header information of animmediately preceding packet when dividing the packet.

(7) The receiving device according to (6) described above,

in which the header information is a synchronous byte, type information,or a data length at the time of division.

(8) The receiving device according to any one of (1) to (5) describedabove,

in which the packet dividing unit adds additional information defined bya transmission protocol when dividing the packet.

(9) The receiving device according to any one of (1) to (8) describedabove,

in which the packet length indicating unit defines the packet length byusing a result of learning the packet length from the packet length withwhich division processing is performed previously.

(10) The receiving device according to any one of (1) to (9) describedabove,

in which the packet length indicating unit defines a range of the packetlength by using a result of learning the packet length from the packetlength with which the division processing is performed previously.

(11) The receiving device according to any one of (1) to (10) describedabove,

in which the packet is a type length value (TLV) packet.

(12) The receiving device according to any one of (1) to (11) describedabove,

in which the packet information is at least one of transmission andmultiplexing configuration control information (TMCC information), slotheader information, and data length information.

(13) The receiving device according to any one of (1) to (11) describedabove,

in which the packet information is at least one of BB Frame headerinformation and data length information.

(14) The receiving device according to claim any one of (1) to (11)described above,

in which the packet information is at least one of divided TLV packetheader information and data length information.

(15) A receiving method, provided with:

analyzing packet information regarding a packet from a transmittedmultiplexed stream;

defining a packet length; and

dividing the multiplexed stream into packets by using at least one ofanalyzed packet information and defined packet length

by a receiving device.

(16) A communicating system provided with:

a transmitting device provided with

a transmitting unit which divides a signal into packets and transmits amultiplexed stream obtained by multiplexing the divided packets; and

a receiving device provided with

an information analyzing unit which analyzes packet informationregarding the packet from the multiplexed stream transmitted by thetransmitting device;

a packet length indicating unit which defines a packet length; and

a packet dividing unit which divides the multiplexed stream into packetsby using at least one of the packet information analyzed by theinformation analyzing unit and the packet length indicating the packetlength defined by the packet length indicating unit.

REFERENCE SIGNS LIST

-   1 Communicating system-   11 Transmitting device-   12 Receiving device-   13 Antenna-   14 Data processing device-   21 Tuner unit-   22 Demodulation processing unit-   23 Error correction decoding processing unit-   24 Variable length packet processing unit-   41 Information analyzing unit-   42 Packet length indicating unit-   43 Packet dividing unit-   201 Cable retransmitting system-   211 Cable retransmitting device-   212 Receiving device-   213 Data processing device-   221 Antenna-   222 Satellite tuner-   223 Convertor/multiplexer-   224 Cable modulator-   225 Transmitting unit-   241 Tuner unit-   242 Demodulation processing unit-   243 Error correction decoding processing unit-   244 Variable length packet processing unit-   251 Information analyzing unit-   252 Packet length indicating unit-   253 Packet dividing unit

1. A receiving device comprising: an information analyzing unit whichanalyzes packet information regarding a packet from a transmittedmultiplexed stream; a packet length indicating unit which defines apacket length; and a packet dividing unit which divides the multiplexedstream into packets by using at least one of the packet informationanalyzed by the information analyzing unit and the packet lengthindicating the packet length defined by the packet length indicatingunit.
 2. The receiving device according to claim 1, wherein the packetdividing unit divides the multiplexed stream into packets by using thepacket length in the packet information analyzed by the informationanalyzing unit or the packet length indicating the packet length definedby the packet length indicating unit according to a comparison resultbetween the packet length in the packet information analyzed by theinformation analyzing unit and a range of the packet length defined bythe packet length indicating unit.
 3. The receiving device according toclaim 2, wherein the packet dividing unit divides the multiplexed streaminto packets by using the packet length in the packet information in acase where it is determined that the packet length in the packetinformation analyzed by the information analyzing unit falls within therange of the packet length defined by the packet length indicating unit.4. The receiving device according to claim 2, wherein the packetdividing unit divides the multiplexed stream into packets by using thepacket length defined by the packet length indicating unit in a casewhere it is determined that the packet length in the packet informationanalyzed by the information analyzing unit is out of the range of thepacket length defined by the packet length indicating unit.
 5. Thereceiving device according to claim 1, wherein, in a case where thepacket divided on the basis of the packet length defined by the packetlength indicating unit is the packet having a non-standard short packetlength, the packet dividing unit adjusts a divided position with animmediately preceding packet length or invalidates the packet having theshort packet length.
 6. The receiving device according to claim 1,wherein the packet dividing unit rewrites header information of animmediately preceding packet when dividing the packet.
 7. The receivingdevice according to claim 6, wherein the header information is asynchronous byte, type information, or a data length at the time ofdivision.
 8. The receiving device according to claim 1, wherein thepacket dividing unit adds additional information defined by atransmission protocol when dividing the packet.
 9. The receiving deviceaccording to claim 1, wherein the packet length indicating unit definesthe packet length by using a result of learning the packet length fromthe packet length with which division processing is performedpreviously.
 10. The receiving device according to claim 1, wherein thepacket length indicating unit defines a range of the packet length byusing a result of learning the packet length from the packet length withwhich the division processing is performed previously.
 11. The receivingdevice according to claim 1, wherein the packet is a type length value(TLV) packet.
 12. The receiving device according to claim 1, wherein thepacket information is at least one of transmission and multiplexingconfiguration control information (TMCC information), slot headerinformation, and data length information.
 13. The receiving deviceaccording to claim 1, wherein the packet information is at least one ofBB Frame header information and data length information.
 14. Thereceiving device according to claim 1, wherein the packet information isat least one of divided TLV packet header information and data lengthinformation.
 15. A receiving method, comprising: analyzing packetinformation regarding a packet from a transmitted multiplexed stream;defining a packet length; and dividing the multiplexed stream intopackets by using at least one of analyzed packet information and definedpacket length by a receiving device.
 16. A communicating systemcomprising: a transmitting device provided with a transmitting unitwhich divides a signal into packets and transmits a multiplexed streamobtained by multiplexing the divided packets; and a receiving deviceprovided with an information analyzing unit which analyzes packetinformation regarding the packet from the multiplexed stream transmittedby the transmitting device; a packet length indicating unit whichdefines a packet length; and a packet dividing unit which divides themultiplexed stream into packets by using at least one of the packetinformation analyzed by the information analyzing unit and the packetlength indicating the packet length defined by the packet lengthindicating unit.